The present invention relates to a method and apparatus for washing both surfaces of a substrate such as a semiconductor wafer and an LCD (liquid crystal device) substrate.
In the manufacturing process of a semiconductor device, a photolithography technology is employed for forming a circuit, an electrode pattern, etc. on a semiconductor wafer. In the photolithography technology, a semiconductor wafer is coated with a photoresist solution. Then, the resist coating film is exposed to light, followed by a developing treatment with a developing solution. It should be noted that, before a series of the resist processing noted above, a front surface of the wafer which is to be coated with a resist solution is washed in order to prevent defect occurrence in the circuit pattern and short-circuiting of the wiring layers. It is also necessary to wash a back surface of the wafer in order to prevent mis-focussing in the light-exposure step and particle generation.
It was customary in the past to use a scrubbing device for brushing both surfaces of a semiconductor wafer, while supplying a washing liquid to the wafer, for washing the wafer. In general, the washing device of this type includes a front surface washing unit, a back surface washing unit, a wafer reversion unit, a heating unit and a cooling unit, which are arranged to have a transfer path sandwiched therebetween. When the washing device is used for washing a semiconductor wafer, the wafer is successively transferred by a transfer mechanism into each of the front surface washing unit, etc. in accordance with a predetermined recipe, thereby applying predetermined treatments to the wafer.
In the washing treatment of this type, however, a wide range of applicability which permits application to different specifications required by various users is required in, for example, the drying treatment. It follows that it is insufficient to apply a washing treatment to a substrate in accordance with a single recipe.